A linear ball bearing device is known which comprises a bearing block having a substantially flat contact surface integrally formed thereon for contact with the object.The bearing block has fastening means for the connection of the bearing block to the object and has a plurality of ball loops which are in each case arranged in radial planes with respect to the axis of the cylindrical shaft. Each of the ball loops comprises a radially inner, load-carrying ball row, a radially outer ball row running in the reverse direction and--close to the axial ends of the bearing block--curved ball deflection rows or junctures for connecting the respective radially inner, load-carrying ball row to the radially outer ball now running in the reverse direction. The radially inner ball rows are supported radially outwardly on axially extending load-carrying surfaces which are provided on a cylindrical inner surface. The load-carrying surfaces extend between guide surfaces spaced in the peripheral direction. The radially outer ball rows run in return channels, the curved ball deflection rows or junctures being guided by a convex toroidal surface directed axially outwardly and by concave semi-circular grooves directed axially inwardly, the guide surfaces and the semi-circular grooves being arranged on a cage sub-assembly. The cage sub-assembly has guide webs extending over the length of the load-carrying surfaces and, on the axial ends of the guide webs, has hook flanges which connect with the latter and which have the semi-circular grooves. Each hook flange has an axially inwardly directed hook end surface which engages an axially outwardly directed channel aperture surface of the respective return channel. Each of these hook flanges has an outer peripheral surface for contact with an inner peripheral surface of the bearing block. The cage sub-assembly is divided into two half cages in a dividing plane normal to the axis and cutting the guide webs.
Such a linear ball bearing has been manufactured commercially and is known from a prospectus "STAR Linear-Set mit Radial-Kugelbuchse" ("STAR Linear Set with Radial ball bush").
In the known embodiment, the ball loops are accommodated in a ball bush which is made separately from the bearing block. This known embodiment has therefore proved successful, because, when the ball loops are accommodated in a ball bush which is separate from the bearing block, this ball bush can be produced in large production runs and subsequently assembled in various forms of bearing blocks. The disadvantages of this known solution, however, have hitherto not been appreciated.
It has now been recognised, however, that certain problems can nevertheless appear in the known embodiment.
By the installation of a ball bush, having ball loops arranged therein, in a bearing block, precision errors accumulate at the bearing block and at the ball bush, so that maintaining the regularly required close tolerances becomes difficult. The spatial superimposition of ball bush and bearing block also leads to large dimensions with corresponding high weight. However, with regard to restricted installation conditions, large dimensions are often undesirable, and high weight leads to increased inertia forces at high accelerations of the object.
It is therefore an object of the present invention to manufacture with high precision a linear ball bearing device of the type described above which has a undiminished basic load rating and undiminished rigidity, but which at the same time has reduced weight and dimenisons.